Method of forming dams



OC. 7, 1941. l lQ E BENNETT ETAL 2,257,727

METHOD OF FORMING DAMS Filed March 4, 1939 ljg.1.

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I gauges land loss of oil in the Patented Oct. 7, 19411 235mm l ME'rnon or FomvnNGnAMs charles E. Bennett, Ridgewood.' and Free. c. Meyer, Wyckoll, N. J., assigner: to The Okon ite-CallenderA Cable Paterson, N. J., a corpo Company,

Incorporated, ration of New Jersey Application Moron 4, 1939, serial No. 259,718 s claims.' (ci. ca -11o) Our invention is directed to a method forvforming dams in pipe lines, more specifically pipe lines containing oil or other liquid. Still more specifically the present' invention provides for forming dams in pipe lines at relatively short intervals and so that tests may be made for leaks in the length or sections between blocks.

One of the advantages of our method resides in the fact that it is relatively inexpensive in that it becomes unnecessary to uncover long lengths of the line and no expensive equipment is necessary.

Broadly speaking, our invention comprehends the freezing of the oil in the pipe line at predetermined points in the line, thereby to block the line, so that the same can be tested for leaks intermediate these blocks or dams.

More specifically our invention comprehends a cooling down of the area the introduction into this'cooled area of a material having a pouring point higher than that of the now cooled material at the area to be blocked. We have found in some cases it may be advantageous to introduce a good thermal .conductor into the pipe line at'the area to be blocked, in'l which case it is not always essential to introduce the material above referred to.

In the accompanying drawing:

Fig. 1 is a part sectional side elevation of a pipe line showing one form practicing our invention; l y

Fig. 2 is a similar view showing another form of equipment; and f Fig. 3 is a similar view showing still another form of equipment.

Referring first of au to 1 ofthe drawing:

of equipmentadapted for of the leak, we excavate the section at each side vof thepoint where it mate location for a few feet is thought the leak is located. 4

Cir

to be blocked and then y Y throughout the area` to 2 designates a pipe line buried in the earth. `This A line, we will assume, is filled with oil from a suitably located storage reservoir and if it should be the pipe line of a well known type of electric cable, it contains one or more insulated electric conductors l which have been drawn into thepipe line and the oil is under pressure.

The storage reservoir is equipped with suitable storage reservoir denotes a leak in the pipe line. If more than one pipe line is fed from the reservoir it will be necessary to make a pressure drop test to determine which line is leaking. The leaking line will lose pressure much `more rapidly than the others. Having determined which line is leaking, it becomes necessary to make a survey of the various sections of the line to determine which section is leaking. In making this survey it is customary to examine the ground for oil pools, loss of vegetation, etc. Having decided upon theV approxil be made between the dams `or matically at I0.

A casing, such as that shown at 6, is then built around the pipe line at the excavated areas. These casings are heat insulated. Wethen ll the casings'with' a refrigerant such as ice and sait, `for example, or with a mixture of gasoline and CO2 ice. We find a satisfactory procedure is to ll or partially fill the casing with gasoline and then add CO2 ice. In this way we are. able to control thev temperature f the refrigerant in the casing, from room temperature down to around -'10 C.

Then the equipment .is allowed to stand for a short time, say for an hour, thoroughly to chill the oil in the line at the casings. It is important at this stage that the oil be chilled uniformly be blocked and that chilling be effected slowly, quick freezing tending to buid up an insulating ring or annulus of 'frozen oil which prevents freezing of the oil at the center of the areato be blocked. We next introduce a compound into the area .to be blocked, .this com-l pound having a pour point higher than that of the chilled oil. This compound Awhich is prechilled is'introduced at as low a temperature as possible, by the pressure gun shown diagram- This gun may be similar to the grease 'guns employed for chassis lubrication and be capable of developing pressures as high as 10,000 lbs. per square inch. The pipe line may be provided with vent pipes I2. The gun can be vattached at 8, and valves 9 may be provided in the charging and vent lines. The introduction of the compound is preferably done in two stages. In other words, part of the compound is introduced, then the equipment is allowed to stand for a short time, before the remainder of the compound is introduced. When the mass at the areas to be blocked has frozen solid, then tests for leaks can blocks. We have obtained good results where an 8%" OD pipe line containing three single conductor cables has been lled with 720 second viscosity oil (Saybolt Universal at 100 F.) with a pour point of 20 F. and a compound such as a mixture of thi-s same oil with rosin to raise itspour point to av tem-- perature of .60 F. More specifically before the compound wask introduced, the pipe was cooled for an hour, then some compound' introduced and freezing 'continued for `four more hours, after which more compound was introduced and freezing continued for several hours more. until the mass of oil surrounded by the casing 6 was f n arrangement provides a solid. About ten gallons of compound were employed and about twelve hours were required to effect a complete seal. By cooling or chilling the pipe -line for some time before introducing the compound the oil in the pipe line at the area surrounded by the casing is thickened and will ing from the spirit and It is to be understood that changes may be made in the process described without departscope of the invention. What we claim is:

1. The process of forming a dam in a pipe line containing a liquid, which -process comprevent dispersion of the compound in the oil of the pipe line except at the site or block is to be formed.

The compound may be removed after completion of the operation by slight heating to drive off the compound through` thevent pipe I2, simiy by closing the valve 9 in the line from the pressure gun and opening the valve 9 in the vent I2.

There is considerable flexibility in our method so far as selection of compound is concerned. For example, instead of employing the compound above mentioned, we may use a compound which is a mixtureuof 95% rosin and 5% oil of say 3000 seconds viscosity (Saybolt Universal at 100 F.) which is frozen solid at 150 F.

In Fig. 2 we have shown a. modified form of at which the dam lequipment in that the pressure gun i4 which corresponds to the gun I of Fig. 1 serves to introduce compound' into the pipe line l2 simultaneously at two separated points.

We have found that the process is considerably speeded up if a thermal conducting material is introduced into the pipe line at the site of the dam. In such event it'is not always essential to introduce the compound such as referred to in connection with our description of Fig. l. Such a variation or modificationis useful with large diameter pipes where some difculty may be experienced due to the oil freezing adjacent the pipe and acting as an insulator'to prevent freezing of the oil nearer the center. In this connection, and with reference to Fig. 3, before the casing 6 is placed in position a copper chain I6, for example, is placed in the pipe line and fairly well fills the pipe line at the dam site. The outer end of the chain is allowed to extend into the refrigerant in the casing 6. This good thermal conducting path and materially shortens the freezing operation. Conductors other than the chain may be employed such as a exible stranded conductor,

Woven wire 0r other flexible metallic conductor. On the other hand, flexible tubes maybe inserted in the oil and a freezing mixture circulated through them. i

It will be seen from all of the foregoing that our invention provides a process whereby dams or blocks may be readily frozen into a pipe line at desired intervals to promote the locating of leaks in the pipe line.

prises introducing a compound into the pipe line at the site of the desired dam, the compound having a. pour point higher than that of the liquid, and freezing the mixture of liquid and compound in situ.

2. The process of forming a dam in an oilcontaining pipe line, which process comprises introducing a compound into the pipe line at the desired site of the dam, the compound having a pour point higher than that of the oil, and freezing the mixture of oil and compound in situ.

3. The process of forming a dam in an oilcontaining pipe line, which process comprises chilling the oil in the pipe line at a predetermined site, until substantially all of the oil at the site is chilled, then introducing a compound into the chilled oil, the compound having a pour point which is higher than the oil, and then freezing the mixture of oil and compound in situ.

4. The process of forming a dam in an oilcontaining pipe line, which process comprises packing a refrigerant about the pipe line at the desired site of the dam, to effect transfer of heat from the oil in the pipe line at said site, thereby to chill the oil, introducing a compound into this chilled oil, the compound having a pour point higher than that of the oil, and then freezing the mixture of oil and compound in situ into a solid mass.

5. The process of forming a dam in an oilcontaining pipe line, which process comprises circulating a refrigerant through the oil in the pipe line at a predetermined site in the pipe line to chill the oil at this site, introducing a compound into the chilled oil, the compound having a pour point higher than the' oil, and then i freezing the mixture of oil and compound in 'introducing into the chilled oil a compound having a pour point higher than the oil, and freezing the mixture of oil and compound in situ.

CHARLES E. BENNE'I'I. FRED C. MEYER. 

